scholarly journals Predicting strength and strain enhancement ratios of circular fiber-reinforced polymer tube confined concrete under axial compression using artificial neural networks

2018 ◽  
Vol 22 (6) ◽  
pp. 1426-1443 ◽  
Author(s):  
Qasim S Khan ◽  
M Neaz Sheikh ◽  
Muhammad NS Hadi
Keyword(s):  
Axial Compression ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Enhancement Ratio ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Concrete Cylinders ◽  
Circular Fiber ◽  
Polymer Tube ◽  
Research Studies

Numerous research studies experimentally investigated the axial compressive behavior of fiber-reinforced polymer tube confined concrete cylinders in the past two decades. However, only a limited number of research studies developed stress–strain models to predict the strength and strain enhancement ratio of fiber-reinforced polymer tube confined concrete cylinders under axial compression. The available strength and strain enhancement ratio models of fiber-reinforced polymer tube confined concrete cylinders are a function of actual confinement ratio only. This study develops strength and strain enhancement ratio models for circular fiber-reinforced polymer tube confined concrete under axial compression based on artificial neural network analyses using Purelin and Tansig transfer functions. The developed strength and strain enhancement ratio models are functions of actual confinement ratio, orientation of fibers, height to diameter ratio, and axial strain in unconfined concrete at peak axial stress. The formulation and performance evaluation of the developed strength and strain enhancement ratio models are carried out using experimental investigation results of 238 circular fiber-reinforced polymer tube confined concrete under concentric axial compression compiled from a database of 599 fiber-reinforced polymer tube confined concrete specimens. The predictions of the developed strength and strain enhancement ratio models match well with the experimental investigation results of the compiled database. The developed strength and strain enhancement ratio models exhibit smaller statistical errors than the available models in the research studies for predicting the strength and strain enhancement ratios of circular fiber-reinforced polymer tube confined concrete under axial compression.

Experimental study of polyester fiber-reinforced polymer confined concrete cylinders

2016 ◽  
Vol 86 (15) ◽  
pp. 1606-1615 ◽  
Author(s):  
Liang Huang ◽  
Xinrui Yang ◽  
Libo Yan ◽  
Kai He ◽  
Hang Li ◽  
...  
Keyword(s):  
Experimental Study ◽  
Polyester Fiber ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Concrete Cylinders

The Effect of Confinement Method and Specimen End Condition on Behavior of FRP-Confined Concrete under Concentric Compression

2013 ◽  
Vol 351-352 ◽  
pp. 650-653 ◽  
Author(s):  
Thomas Vincent ◽  
Togay Ozbakkloglu
Keyword(s):  
Experimental Investigation ◽  
Cross Sections ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Fiber Reinforced ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Reinforced Polymer ◽  
Concrete Cylinders ◽  
Frp Tubes

This paper presents an experimental investigation on the influence of confinement method and specimen end condition on axial compressive behavior of fiber reinforced polymer (FRP)-confined concrete. A total of 12 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were tested. Half of these specimens were manufactured as concrete-filled FRP tubes (CFFTs) and the remaining half were FRP-wrapped concrete cylinders. The effect of specimen end condition was examined on both CFFTs and FRP-wrapped specimens. This parameter was selected to study the influence of loading the FRP jacket on the axial compressive behavior. In this paper the experimentally recorded stress-strain relationships are presented graphically and key experimental outcomes discussed. The results indicate that the performance of FRP-wrapped specimens is similar to that of CFFT specimens and the influence of specimen end condition is negligible.

scholarly journals Ductility Evaluation of Damaged Recycled Aggregate Concrete Columns Repaired With Carbon Fiber-Reinforced Polymer and Large Rupture Strain FRP

2020 ◽  
Vol 7 ◽  
Author(s):  
Pengda Li ◽  
Yao Zhao ◽  
Xu Long ◽  
Yingwu Zhou ◽  
Zhenyuan Chen
Keyword(s):  
Concrete Columns ◽  
Recycled Aggregate Concrete ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Recycled Aggregate ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Reinforced Polymer ◽  
Concrete Cylinders

The inherent defects of recycled aggregate concrete (RAC) include the complex interfacial transition zone (ITZ) and the many micro-cracks that appear during its producing process, which result in some inferior mechanical properties compared with natural aggregate concrete (NAC). This drawback usually prevents RAC from being selected for structural purposes. Existing research has shown that the strength and ductility of damaged concrete in compression members can be significantly enhanced through external confinement using fiber-reinforced polymer (FRP) wraps. This application has been widely used in concrete structural repair and retrofitting technology. However, research on the effects of RAC damage coupled with different load damage conditions is rare, as is information on the mechanical properties of RAC reinforced with FRP jackets. This paper presents the results of an experimental study on the behavior of pre-damaged recycled aggregate concrete cylinders that were repaired with carbon fiber-reinforced polymer (CFRP) or large rupture strain (LRS)-FRP jackets. Tests were conducted on 58 concrete cylinders with variations in the replacement ratio, damage levels, and FRP properties. Test results demonstrated that the ultimate strain and strength of damaged recycled aggregate concrete could be significantly enhanced by FRP jackets and that aggregate quality plays a vital role in the strength of confined concrete. Also, the energy absorption of CFRP- and LRS-FRP-confined RAC were evaluated. The analysis indicated that, compared with CFRP-confined RAC, LRS-FRP can greatly improve the energy absorption capacity of RAC; thus, LRS-FRP confined concrete has a good potential to achieve a ductile design for concrete columns, especially when used in seismic reinforcement.

scholarly journals Failure and impact resistance analysis of plain and fiber-reinforced-polymer confined concrete cylinders under axial impact loads

2018 ◽  
Vol 9 (1) ◽  
pp. 4-23 ◽  
Author(s):  
Thong M Pham ◽  
Wensu Chen ◽  
Hong Hao
Keyword(s):  
Carbon Fiber ◽  
Glass Fiber ◽  
Impact Resistance ◽  
Numerical Results ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Concrete Cylinders ◽  
The Impact

This study conducts an experimental and numerical investigation on the failure and impact resistance of plain and fiber-reinforced polymer-confined concrete. The impact resistance of concrete cylinders wrapped with different types of fibers including carbon fiber and glass fiber is examined. Drop-weight tests are utilized to conduct the impact tests while the numerical simulation is conducted using LS-DYNA. The experimental and numerical results have proved that fiber-reinforced polymer can be efficiently used to improve the impact resistance of concrete cylinders. In general, fiber-reinforced polymer ruptures at a lower strain than those in static tests and the rupture strain of glass fiber is much higher than that of carbon fiber. The findings in the experimental tests are confirmed by the numerical results. Glass fiber, therefore, exhibits a much better performance than carbon fiber. It is recommended to use glass fiber to enhance the impact resistance of concrete structures strengthened with fiber-reinforced polymer. In addition, the stress evolution of the specimens is analyzed to investigate the failure mechanism.

Hybrid basalt/flax fibers reinforced polymer composites and their use in confinement of concrete cylinders

2019 ◽  
Vol 23 (5) ◽  
pp. 941-953
Author(s):  
Yuanyuan Xia ◽  
Guijun Xian
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Flax Fibers ◽  
Reinforced Polymer ◽  
Concrete Cylinders ◽  
Relationship Of

Flax fiber–reinforced polymer composites were determined to be effective in confinement of concrete cylinders. Flax fibers exhibit strong intrinsic hydrophilic properties and relatively inferior mechanical properties; therefore, combining them with mineral-based natural fiber (i.e. basalt fibers) was proposed. In the present study, unidirectional flax–basalt hybrid fiber reinforced polymer plates and tubes were prepared using a filament-winding process. The mechanical properties of the fiber-reinforced polymer plates and compressive properties of the concrete-filled fiber-reinforced polymer tubes were studied. Compared to those of flax fiber–reinforced polymer, hybrid fiber–reinforced polymers exhibited linear rather than bilinear stress–strain curves and enhanced tensile properties. The lateral–axial relationship of the hybrid fiber reinforced polymer–confined concrete cylinders can be well predicted by the classic model for glass- or carbon-based fiber-reinforced polymer-confined concrete cylinders, however, the axial stress–strain cannot. In addition, the lateral–axial relationship of the hybrid fiber reinforced polymer–confined cylinders depends on the arrangement of the fiber layers.

Effect of fiber angles on normal- and high-strength concrete-filled fiber-reinforced polymer tubes under monotonic axial compression

2019 ◽  
Vol 23 (5) ◽  
pp. 924-940
Author(s):  
Bing Zhang ◽  
Xia-Min Hu ◽  
Qing Zhao ◽  
Tao Huang ◽  
Ning-Yuan Zhang ◽  
...  
Keyword(s):  
Axial Compression ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Absolute Value ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Polymer Tube ◽  
Polymer Tubes

Concrete-filled fiber-reinforced polymer tubes are a novel form of composite columns, which are particularly attractive for structural members in harsh environments and seismic regions due to their corrosion resistance and ductile behavior. Over the past two decades, many studies have been conducted on concrete-filled fiber-reinforced polymer tubes under axial compression, and many stress–strain models have been proposed. However, existing studies mainly focused on concrete-filled fiber-reinforced polymer tubes with only hoop fibers. In order to investigate the effect of fiber angles (i.e. the fiber angle between the fiber orientation and the longitudinal axis of fiber-reinforced polymer tube), this study conducted axial compression tests of 42 concrete-filled fiber-reinforced polymer tubes with ±80°, ±60°, or ±45° fiber angles. These concrete-filled fiber-reinforced polymer tubes were constructed using normal-strength concrete or high-strength concrete. Fiber-reinforced polymer tube thickness was also investigated as an important parameter. In order to clarify the effect of fiber angles on the properties of fiber-reinforced polymer tubes, axial compression tests on 15 short fiber-reinforced polymer tubes and tensile split-disk tests on 75 fiber-reinforced polymer rings were conducted. Experimental results indicate that fiber angles had significant influences on the hoop properties of fiber-reinforced polymer tube; the confinement effect of fiber-reinforced polymer tube and the peak stress of the confined concrete decreased with the decrease of the absolute value of fiber angles, while the ultimate strain of the confined concrete increased with the decrease of the absolute value of fiber angles. Two existing stress–strain models, which were developed mainly on test results of concrete confined by fiber-reinforced polymer tubes with only hoop fibers, are capable of providing reasonably accurate predictions for concrete-filled fiber-reinforced polymer tubes with ±80° and ±60° fiber angles, but it underestimates the ultimate axial strain of concrete-filled fiber-reinforced polymer tubes with ±45° fiber angles.

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